The present invention relates to an ozone generating apparatus most suitable for use for a water quality improving apparatus by which the amount of oxygen dissolved in water is increased, and chlorine or carcinogenic noxious substances such as trihalomethanes contained in city water are decomposed, and particularly to an ozone generating apparatus whose ozone generating efficiency is high. The present invention also relates to a water quality improving apparatus using the ozone generating means to prevent various common bacteria from reproducing as well as to improve the decomposition rate of carcinogens.
It is well known that chlorine is conventionally mixed into city water for the sterilization. The sterilization with chlorine have greatly contributed to the prevention of infectious epidemics after the war. However, it has been found that the chlorine reacts chemically with humic acids naturally contained in the raw water that is taken in thereby leading to the formation of carcinogenic substances such as trihalomethanes. Particularly, the influence of this on babies and infants is a serious problem, and it is guided to boil the water to be used for the preparation of milk from powdered milk or the like and to cool the prepared milk for feeding.
Various water treating apparatuses including water purifiers have been developed, and there are devised a type using a filter such as a microfilter for removing foreign matter and various bacteria, and a type using an ion exchanger for increasing ions in water. Further, recently, water purifiers equipped with an ozonizer are devised in which the idea is placed on the biocidal and purifying actions of ozone. The ozonizer used in these purifiers for converting oxygen to ozone uses a system wherein silent discharge is effected in dry air or a system wherein ultraviolet light having a wavelength of 184.9 nm is generated by a quarts glass tube thereby producing ozone. The system for obtaining ozone by carrying out silent discharge in dry air has problems that the apparatus becomes large-sized, and NO.sub.x harmful to the human body is generated, and therefore, for a small-sized ozonizer, there is an increasing tendency to employ the system using a quartz glass tube. For the ozonizer using a quartz glass tube, there is a system wherein one end of a box containing a quartz glass tube is opened and the other end is connected to a blower placed outside so that the air and the ozone in the box are blown simultaneously (first system), and a system wherein pressurized air is blown into one end of a box containing a quartz glass tube, and the discharge is effected from the other end (second system).
However, in the conventional first system using a quartz glass tube, air and ozone are simultaneously taken into the blower, and therefore there is a problem that the inside of the blower is corroded by the strong oxidizing power of the ozone. In the second system using a quartz glass tube, since pressurized air is blown around the quartz glass tube all the time, there is a problem that the surface of the quartz tube is cooled. This problem is serious because the ozone generating efficiency of a quartz glass tube becomes maximum when its temperature is about 60.degree. to 70.degree. C. and the ozone generating efficiency decreases when the surface of the quartz glass tube is cooled.